Many athletes and non-athletes utilize weight lifting or weight training exercises to build strength and muscles. Traditionally, these exercises are performed by using free weights, such as barbells, weighted plates, dumbbells, etc. There are also a number of exercise machines that are designed to maximize the effect of training on desired muscle groups in a variety of different exercise routines.
One exercise movement that is considered to be particularly important is referred to as a leg press. A leg press involves the straightening or extension of the legs from a bent or flexed position against weighted resistance. The exercise is performed with the user either seated in an inclined position or pushing at an approximately perpendicular angle against the weight resistance, or lying on the back and pushing upward against the weight resistance.
Typical leg press machines are commonly referred to as “45 degree leg press machines” because the angle of the moving resistance relative to the horizontal surface that the machine sits on is 45 degrees. With common leg press machines, the angle of the torso relative to the legs in full extension is approximately 90 degrees.
The leg press is particularly effective in building the hamstrings muscles of the legs. It is also particularly effective in building the quadriceps muscles of the legs. It can also strengthen the hip muscles, lower leg muscles and generally all of the muscles of the legs. Perhaps more importantly, exercising the muscles associated with the leg press motion develops the general “thrusting” capability and strength of the legs.
While the leg press exercise develops some of the strongest and largest muscles of the human body, the user may need to overcome force vectors and movement patterns created by these machines, which are not congruent with normal human movement. The heavier weights, typically used on these machines, which are moved by the powerful leg muscles, can cause the lower back to go into an unhealthy flexion, or outward rounding. When this occurs, the lower spine is put at risk of serious injury.
Because the main concentric portion of this exercise begins with the legs in a retracted position, initial stress on the ankles, hips and particularly the knees and the lower back can be substantial. It is important for the user to retain a correct and safe lower back posture when using such a machine, so that the lower back remains in a healthy extension during the exercise and it is not forced into a rounded or flexed position, especially when using a heavy resistance.
While compressive forces on joints associated with the leg press exercise is simply unavoidable, this joint stress can be and should be made positive. This is achieved by designing and creating special angles on the seat, backrest and foot press plates, particularly at the initial stages of the moving leg press exercise, which are healthier and more natural and congruent with normal human biomechanical movements. Further, these more preferable and optimal angles will allow for greater transfer of strength gains and increased human performance from using such a leg press machine into sports, work and life. This will be a safer and more effective creation and transfer of strength and performance benefits, than a typical leg press will allow.
Leg press machines are designed to provide a safer but similar squatting exercise by eliminating the requirements of balance and stability to complete the free weight movements and removing the active inclusion of the back muscles to push the resistance by flexion and extension forward of the hips. These machines provide a starting position whereby the legs are semi-extended. The resistance is then pushed out such that the legs are completely extended. The legs then bend to yield the resistance as the user's legs are compressed into the squatting position with the knees bent. The user will then push the resistance out with their legs such that they finish with their knees fully extended and legs straightened at the finish.
While the movement is similar to a free weight squat or dead lift exercise, the leg press machines do not provide the same body alignment, joint angles, force direction or posture as those standing free weight movements. The reason for this is that they fix the user's body into a locked pattern, whereby the angle of the backrest and the footplate will not allow a movement pattern which is similar to free weight movements such as squats or dead-lifts.
During a free weight squat or dead lift movement the body is constantly making minor adjustments to keep the feet, knees and back in proper alignment, such that the resistance is over the user's center of gravity while they complete the movement. This adjustment does not take place just at the beginning or at the end of the exercise; it happens continuously throughout the entire movement. The most optimal movement pattern of the resistance during these free weight exercises is a vertical or a straight line. This is the most efficient and desired movement pattern, whereby the resistance moves in a straight line directly over one's center of mass and center of gravity.
Fitness machines, such as leg press machines, by their very nature do not require the neutralizing, stabilizing, reinforcing and balancing muscles that are required in valuable free weight exercises such as squats or dead-lifts. In addition, they do not require the physical abilities inherent in free weight exercises, such as squats or dead lifts, where the resistance must be balanced and lifted by the user at the same time in order to successfully complete such exercises. In addition, compared to movements such as a free weight squat or dead lift, with the leg press the force vectors are reversed. Yet, the same joint angles and lines of force that exist in the lowest part of the movement and during the concentric drive upward can be approximated in a leg press to better approximate these more natural movement. In addition, the same close to vertical movement pattern required in a free weight squat or dead lift can also be approximated.
Typical leg press machines do not provide the correct approximation of joint angles, lines of force or straight-line movement patterns inherent in more natural free weight movements, such as squats or dead lifts. It is desired to have a leg press machine that can provide and replicate the natural human movement in relation to the joint angles, lines of force and direction of movement and forms of resistance. The present machine is invented to provide such a function.